A light-emitting-diode (LED) lamp has the advantages of high brightness, high reliability, extended usable life, and low power consumption, and therefore has been widely applied in different fields, such as signboards and general illumination.
Conventionally, an LED lamp includes a base portion and a lamp portion, with LED chips provided in the lamp portion. And, an LED driving unit is provided in the base portion for driving the LED chips to emit light.
The conventional LED lamp has a one-piece structure with integrally formed base portion and lamp portion. While the one-piece LED lamp enables convenient installation thereof, it has the following disadvantages in practical use thereof:    1. When emitting light, the LED lamp also generates a large quantity of heat. In the conventional one-piece LED lamp, the lamp portion and the base portion are not properly spaced from each other. Therefore, the heat generated by the LED lamp could not be effectively dissipated into surrounding air. As a result, the generated heat will stagnate in the LED lamp to adversely affect the lighting efficiency and usable life of the LED lamp.    2. In general, an LED chip has a long service life about fifty thousand hours. On the other hand, the LED driving unit is composed of various electronic elements and generally has a service life shorter than that of the LED chip. When the LED driving unit is damaged, the whole LED lamp will become useless and be discarded. That is, since the base portion and the lamp portion of the conventional LED lamp are integrally formed, when any one of the lamp portion and the base portion of the LED lamp is damaged, it is impossible to just replace the damaged lamp portion or base portion. Instead, the whole LED lamp must be discarded and replaced with a new one. This forms an unnecessary waste to increase the user's burden and does not meet the requirement for environmental protection.    3. Since the base portion and the lamp portion of the conventional LED lamp are integrally formed, it is impossible for a user to freely change the lamp portion to another one having a different shape, size, light color, etc.
Therefore, the conventional one-piece LED lamp has relatively poor applicability and design flexibility, and requires improvements.